python 寻找离散序列极值点的方法

import numpy as np 
import pylab as pl
import matplotlib.pyplot as plt
import scipy.signal as signal
x=np.array([
  0, 6, 25, 20, 15, 8, 15, 6, 0, 6, 0, -5, -15, -3, 4, 10, 8, 13, 8, 10, 3,
  1, 20, 7, 3, 0 ])
plt.figure(figsize=(16,4))
plt.plot(np.arange(len(x)),x)
print x[signal.argrelextrema(x, np.greater)]
print signal.argrelextrema(x, np.greater)

plt.plot(signal.argrelextrema(x,np.greater)[0],x[signal.argrelextrema(x, np.greater)],'o')
plt.plot(signal.argrelextrema(-x,np.greater)[0],x[signal.argrelextrema(-x, np.greater)],'+')
# plt.plot(peakutils.index(-x),x[peakutils.index(-x)],'*')
plt.show()

[25 15 6 10 13 10 20]
(array([ 2, 6, 9, 15, 17, 19, 22]),)

x=np.array([
  0, 15, 15, 15, 15, 8, 15, 6, 0, 6, 0, -5, -15, -3, 4, 10, 8, 13, 8, 10, 3,
  1, 20, 7, 3, 0 ])
plt.figure(figsize=(16,4))
plt.plot(np.arange(len(x)),x)
print x[signal.argrelextrema(x, np.greater)]
print signal.argrelextrema(x, np.greater)

plt.plot(signal.argrelextrema(x,np.greater)[0],x[signal.argrelextrema(x, np.greater)],'o')
plt.plot(signal.argrelextrema(x,np.less)[0],x[signal.argrelextrema(x, np.less)],'+')
plt.show()

[15 6 10 13 10 20]
(array([ 6, 9, 15, 17, 19, 22]),)